Process for direct heating of digesters with forced circulation



March 10, 1925.

E. MORTERUD PROCESS FOR DIRECT HEATING OF'DIGESTERS WITH FORCED CIRCULATION Filed March 10, 1924 1 Z77V/7r0/ 5 Marne/U0 gu ,%a ra rqfija Patented er. id, 192.

PB GUESS FOR DIRECT HEATING OF DIGESTER$ WITH FORCES; CIRCULATION.

Application filed March 10, 1924. Serial No. 698,338.

To all whom it may concern:

Be it known that I, EINAR MORTERUD, engineer, a subject of the King of Norway, residing at Torderod, near Moss, Norway,

have invented certain new and useful Improvements in Processes for Directl-Ieating of Digesters with Forced Circulation; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

The present invention relates to pulp digesters with forced circulation and direct heating.

The direct heating of pulp digesters by means of steam generally takes place by introducing jets of steam into the liquid which has the effect of causing clashing of the liquid surfaces against each other upon the condensing of the steam which is intro 25 duced. This clashingcauses a number of inconveniences, such as noise, liberation of gases and shocks in the digester.

The present invention has for its object a method for the direct heating of pulp digesters, in which the above mentioned drawbacks are avoided. The method consists inintroducing the circulated liquid in the form of s rays, films or the like into a' space, in whit: i the steam may surround the liquid freely and condense against the liquid surfades without causin shocks.

The eiiiciency of the eating transmission between steam and liquid in this manner is equivalent to the efficiency of the known method; and the final result is a mixture of condensed steam and liquid as in ordinary direct heating.

As it will be understood it is necessary that the condensing space is under a suflicient pressure to prevent the device from operating as a jet condenser. This pressure may be obtained either by means of surplus steam, so as to make the liquid surface insufiicient for full condensation, or by the presence of a non-condensing gas.

the digester liquid, it is necessary that the with pulp and acid up to line a, b.

heater and S y In order to prevent liberation of gas from the like is again collected with the least possible shock effect, for instance, by checking the fall of the liquid or letting the liquid drop from a small height.

On the drawing Fig. l is a diagranunatical section of the sulphitc digester for carrying out the present methoc Fig. 2 illustrates a modified form of digester.

Fig. 3 shows a further modification, and

Fig. 4 a still further modification.

011 Fig. 1 A is the digester, which is provided with a sieve B. The digester is filled The acid is circulated by means of pump Q through tubes 0, (Z and is distributed in, the form of a spray through the perforated tubes e in the top of the cooker. Steam is .introduced through tube 9, which may preferably also be perforated. The top of the digester then qperates as a sprayand drop- 2 gas is the medium which serves to maintain the pressure.

On the modification illustrated on Fig. 2 the heater is formed by a separate vessel 1). The circulated liquid is pumped to the spray member 6 of this vessel and is conducted to the top of the digester.

According to the arrangement shown on Fig. 3 the heating vessel 1) is mounted below the digester, and the pump serves to transfer liquid from the bottom of the heating vessel D to the top of the digester A. A tube It connects the top of the heating vesorder to maintain the pressure.

According to the iuither modification illustrated on Fig. 4- the heating vessel D is supplied with liquid from the upper part of the digester, and then liqiiid is transferred from the bottom of heating vessel D to the lower part of digester A.

Claims 1. In a process for digesting pul where forced circulation of the divesting liquid is 'sel with the gas space of the digester in 4 maintained, she .method which consists in ting the'condensing heat of the steam to extended liquid surfaces withom causing shocks or splashes. 3. The combination with a digestei for pulp of a. spray cendenser, means for introdncing heating steam into said condenser and means for circulating the digesting liquid through said digest-er and vsaid spray condenser.

4. The combination with a pulp digestei' of a spray condenser separate from the digestei', means for introducing heating steam 'digester,

in said condenser and means fer chrcniating the digesting liquid through said digester and said condenser;

5. The combination with a pulp digester of a spray condenser separate from said means for introducing jetting steam in said spray condenser, means for circulating the digesting liquid through said spray condenser and said dige'ster and means for maintaining in the said condenser the same pressure as in the digesten In testimony that I claim the foregoing as my invention, 5 have signed my name in presence of two subscribing Witnesses.

MURTERUD,

Witnesses:

DAGNY Ssvmsnn, S. Gonmomniw. 

